Individuals and organizations often seek to authenticate messages, whether they are sent by hand carry, mail, email, or other methods. Historically, individuals have signed their messages in ink, or sealed them with a particular or unique wax seal. Unfortunately, these historical methods may be vulnerable to attacks by others who impersonate or forge the signature or seal.
In other arts, individuals and organizations often seek to encrypt their communications. For examples, an author of a message may encode the message using a cipher, and the recipient may decode the message using the same cypher. Unfortunately, in these systems, both the author and the recipient may need to share the same cypher or symmetric key. That requirement raises the question of how to safely keep secret, transmit, and/or encrypt the cypher itself. In view of the above, some individuals have developed and used digital signatures, which may not suffer from some of these disadvantages, as further discussed below.
In all of the above cases, however, there is no quick and efficient manner for a user to look at a document and authenticate the document without substantial manual intervention. For example, the user may need to stop reading the document, feed it into a manual scanner, and then work on a desktop computer to process the scan results in authentication software. What is needed, therefore, are improved systems and methods for validating digital signatures.